Glass-metal or ceramic-metal sealed two-piece microwave coaxial sensor and placement at a vertical venturi

ABSTRACT

Electromagnetic probes for analyzing a flowing multi-phase fluid are described herein. The probes generally use a probe assembly for measuring liquid properties in a multiphase fluid flowing in a conduit, the probe assembly comprising a first member with a probe portion and a connection portion, the probe portion having a central bore with a conductor and a pressure-resistant insulator surrounding the conductor, the conductor extending from an opening at a distal end of the probe portion into the connection portion, the connection portion having a connector coupled to a distal end of the connection portion, the connection portion having a seal face with a groove extending around the probe portion; and a second member that, when assembled, is in direct contact with the first member at the distal end of the connection portion to apply compression and to retain the first member against a wall of the conduit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.17/249,368, filed on Mar. 1, 2021, which claims the benefit of SingaporePatent Application Serial No. 10202001816R filed on Feb. 28, 2020. Eachof the above applications is incorporated herein by reference in itsentirety.

BACKGROUND Field

This disclosure relates to multiphase flow measurement devices and moreparticularly to multiphase-flow electromagnetic microwave reflectionsensors that may be used standalone or with multiphase flow meters atdownhole, surface, or subsea locations.

Description of the Related Art

Wells are generally drilled into subsurface rocks to access fluids, suchas hydrocarbons, stored in subterranean formations. The subterraneanfluids can be produced from these wells through known techniques.Operators may want to know certain characteristics of produced fluids tofacilitate efficient and economic exploration and production. Forexample, operators may want to know flow rates of produced fluids. Theseproduced fluids are often multiphase fluids (e.g., those having somecombination of water, oil, and gas), making measurement of the flowrates more complex.

Various systems can be used to determine flow rates for multiphasefluids. In some systems, multiphase fluids are separated into theirconstituent phases and these phases are then individually measured byusing single-phase flow meters to determine flow rates. Other systemsinclude multiphase flow meters that can be used to measure flow rates ofmultiphase fluids without separation. These multiphase flow meters maybe smaller and lighter than traditional separators equipped withsingle-phase flow meters, and the ability to measure flow rates withoutseparation may be desirable in some instances. Both the traditionalseparator systems and the multiphase flow meter systems can also be usedto determine certain other fluid characteristics of interest.

It is also desirable to determine properties of the multiphase mixture,such as the presence, fraction, and salinity of water in the mixture,and the water-in-liquid ratio, as this provides information aboutproduced and/or injected water in the mixture, about the (subsea)flow-assurance measures needed to prevent hydrate formation and/orpipeline corrosion, and may affect other measurements being made on themultiphase mixture. Microwave sensors for the measurement of multiphaseflows can be used with multiphase flow meters to determine watersalinity, water fraction, and water-in-liquid-ratio (WLR or water-cut).

The use of electromagnetic (EM) methods, such as microwaves, has beensuggested because of their high measurement sensitivity to the presenceof the water phase in a multiphase flow (water permittivity/conductivityis much higher than the permittivity/conductivity of the hydrocarbonoil-gas phases). For example, U.S. Pat. No. 6,831,470, assigned toSchlumberger, shows that the fluid-contacting front-end of a microwaveopen-ended coaxial probe (an EM sensor) has a pressure-integrityglass-to-metal seal acting as a first pressure barrier (where the glassis a good electrical insulator, or low-loss dielectric material). Theback-end of the probe may have an integral N-type connector of 50-ohmcharacteristic impedance. The measurement probe front-aperture ismounted flush with the pipe wall of a measurement pipe section. Theprobe is connected through the N-type connector to the microwaveelectronics housed in an explosion-proof enclosure by the use of a shortmicrowave coaxial cable/adaptor with no pressure barrier. A bulky andsometimes expensive enclosure is needed as a second pressure barrier tocontain the process fluids in case the pressure-barrier formed by theprobe's glass-to-metal seal fails.

U.S. Pat. No. 9,638,556, issued to Schlumberger (entitled “Compactmicrowave water-conductivity probe with integral second pressurebarrier”), describes methods and devices for measuring fluid propertiesby using an electromagnetic (EM) sensor. The electromagnetic sensorincludes a coaxial probe body having a first integral pressure barrierand a second integral pressure barrier formed from coaxial-feedthroughconnector. The first integral pressure barrier and the second integralpressure barrier have a desired characteristic impedance.

U.S. Pat. No. 10,330,622, issued to Schlumberger (entitled “Glass-sealedelectrode”), describes an electrode (a coaxial probe) that includes a(center) conductor, an insulator (such as glass), and a metallichousing. The insulator is positioned at least partially around theconductor. The housing is positioned at least partially around theinsulator. An upper surface of the insulator may be at least partiallyconcave, an outer surface of the housing may have a groove formedtherein, or both.

SUMMARY

Embodiments described herein provide a probe assembly for measuringliquid properties in a multiphase fluid flowing in a conduit, the probeassembly comprising a first member with a probe portion and a connectionportion, the probe portion having a central bore with a conductor and apressure-resistant insulator surrounding the conductor, the conductorextending from an opening at a distal end of the probe portion into theconnection portion, the connection portion having a connector coupled toa distal end of the connection portion, the connection portion having aseal face with a groove extending around the probe portion; and a secondmember that, when assembled, is in direct contact with the first memberat the distal end of the connection portion to apply compression and toretain the first member against a wall of the conduit.

Other embodiments provide an apparatus for analyzing a flowingmultiphase fluid, the apparatus comprising a conduit; and an open-endedmicrowave probe assembly disposed in fluid communication with theconduit through a wall of the conduit, the conduit having a firstcoupling structure, the probe assembly comprising a first member with aprobe portion and a connection portion, the probe portion having acentral bore with a conductor and a pressure-resistant insulatorsurrounding the conductor, the connection portion having a coaxialconnector coupled to a distal end of the connection portion andconnected to the conductor, the connection portion having a seal facewith a groove extending around the probe portion, and a seal memberdisposed in the groove, the probe portion extending through the firstcoupling structure and the seal face of the connection portion insealing contact with the wall of the conduit; and a second member havinga second coupling structure for engaging with the first couplingstructure.

Other embodiments provide a method of analyzing liquid properties of aflowing multiphase fluid, the method comprising disposing an open-endedmicrowave probe assembly in a port formed in a flow containmentstructure of a flow system carrying the flowing multiphase fluid, theport having a first coupling structure, the probe assembly comprising afirst member with a probe portion and a connection portion, the probeportion having a central bore with a concentric conductor and apressure-resistant insulator surrounding the concentric conductor, theconnection portion having a connector coupled to a distal end of theconnection portion and connected with the concentric conductor, theconnection portion having a seal face with a groove extending around theprobe portion, and a seal member disposed in the groove, the seal faceof the connection portion in sealing contact with a wall of the flowcontainment structure; and a second member having a second couplingstructure that couples with the first coupling structure to applycompression to the distal end of the connection portion to seal the sealface against the wall of the flow containment structure; and energizingthe concentric conductor by applying radio frequency energy to theconnector.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain embodiments of the disclosure will hereafter be described withreference to the drawings, wherein like reference numerals denote likeelements. It should be understood, however, that the accompanyingdrawings illustrate only the various implementations described hereinand are not meant to limit the scope of various technologies describedherein. The drawings show and describe various embodiments of thecurrent disclosure.

FIG. 1 shows a flow measurement apparatus for analyzing flow of amultiphase fluid.

FIG. 2 is an elevation view of a front piece for an EM probe assembly,according to one embodiment.

FIG. 3A is a cross-sectional view of a front piece for an EM probeassembly according to another embodiment.

FIG. 3B is a cross-sectional view of a front piece for an EM probeassembly according to another embodiment.

FIGS. 4A-4C are perspective cross-sectional views of other differentembodiments of a front piece for an EM probe assembly.

FIG. 5 is a perspective cross-sectional view of a probe assemblyaccording to one embodiment.

FIG. 6 is a perspective cross-sectional view of a probe assemblyaccording to another embodiment.

FIGS. 7-9 are perspective cross-sectional views of different apparatusembodiments for analyzing a flowing multi-phase fluid.

FIG. 10 is a graphical depiction of a multiphase fluid flowing in aVenturi device measurement apparatus, the graphical depiction showingliquid content at different locations in the multiphase fluid.

DETAILED DESCRIPTION

In the following description, numerous details are set forth to providean understanding of the present disclosure. It will be understood bythose skilled in the art, however, that the embodiments of the presentdisclosure may be practiced without these details and that numerousvariations or modifications from the described embodiments may bepossible.

In the specification and appended claims: the terms “connect”,“connection”, “connected”, “in connection with”, and “connecting” areused to mean “in direct connection with” or “in connection with via oneor more elements”; and the term “set” is used to mean “one element” or“more than one element”. Further, the terms “couple”, “coupling”,“coupled”, “coupled together”, and “coupled with” are used to mean“directly coupled together” or “coupled together via one or moreelements”. As used herein, the terms “up” and “down”, “upper” and“lower”, “upwardly” and downwardly”, “upstream” and “downstream”;“above” and “below”; and other like terms indicating relative positionsabove or below a given point or element are used in this description tomore clearly describe some embodiments of the disclosure.

Electromagnetic sensors, such as microwave open-ended coaxial probes,for water property detection of multiphase flows may be used withmultiphase flow meters to determine water conductivity or salinity,water fraction, and water-in-liquid-ratio (WLR or water-cut). To improvethe detectability of the onset of first water and changes in the waterconductivity (salinity) or changes in the concentration of ahydrate-inhibitor in water, it has been discovered throughmultiphase-flow experimental studies that an electromagnetic microwavesensor or sensor(s) may be installed in the liquid-rich locations of ablind-tee inlet arrangement. A blind-tee inlet is often used as aflow-mixing pipework for a vertically-installed multiphase flowmeter,such as a multiphase flow meter based on Venturi meter and multi-energygamma-ray measurement section, or an electrical impedance measurementsection, or a microwave transmission-resonance measurement section.

In one embodiment, a two-piece microwave coaxial probe orelectromagnetic sensor has a single short or long pressure barrier(insulator) embedded in the (probe body) front piece (first member). Thefront piece has an alloy (e.g., Inconel) body and a concentric conductor(made of e.g. cemented carbide), bonded by single short or long glass-or ceramic-metal seal(s) (insulator). The microwave coaxial probe orelectromagnetic sensor is designed to have a desired characteristicimpedance (e.g. ca. 50 Ohms). The front of the probe flat or concavede.g. glass surface aperture is in direct contact with process fluid andis substantially flush-mounted at the inner-wall liquid-rich region of aflow containment structure. An appropriately-designed protruding feature(wall member) may be incorporated near the front aperture for localliquid enrichment. An off-the-shelf radio frequency (RF) coaxialconnector is attached to and in good electrical coupling with theprobe's concentric conductor and affixed to the back end (connectionportion) of the front piece, such as by screws. The back piece (secondmember) is designed to provide compressive support to the front piece inthe case of face seal (seal face) so that a C-ring or an O-ring (sealmember) on the front piece can be squeezed against the outer pipe wallof a pressure vessel/pipeline body and seal against process flowpressure (e.g., 5000 psi). A rod/piston seal is another possibility toseal against pressure. The back piece itself is fixed to the pressurevessel/pipeline body by, for example, a single (e.g., M33) thread or bya multiple-bolt back flange.

An electromagnetic (EM) sensor may be used to determine the Water LiquidRatio (WLR) and water salinity of oil-water-gas multiphase flows in anupstream oil-gas production pipeline. The system is based on microwavereflection measurement method and the EM sensor is to transmit microwavesignal (generated by an appropriate electronics circuitry located awayfrom the probe assembly) and detect (using the same circuitry) thereflected microwave signal by the multiphase flow. The EM sensor sensingaperture, with a flat or concaved insulator (e.g. glass) surface, is indirect contact with high pressure, high temperature and corrosiveprocess flow. The front sensing aperture of the EM sensor issubstantially flush-mounted at the near inner-wall (locally liquid-rich)region of the pipeline section in order to make good WLR and brinesalinity measurements. The EM sensors for performing microwavereflection measurement may be based on open-ended coaxial probe designwith glass-metal or ceramic-metal high-pressure seals, such as thosedisclosed in U.S. Pat. Nos. 9,638,556 and 10,330,622, issued toSchlumberger.

FIG. 1 shows a flow measurement apparatus 100 for analyzing flow of amultiphase fluid. Several locations are shown where an EM sensor can beinstalled at various locations of one or more flow containmentstructures, such as a conduit, blind pipe, or flange, in a flow systemto yield good WLR and brine salinity measurements of the flowingmultiphase fluid. A first EM sensor 102 is shown installed at a topblind flange 112 downstream of a vertical upflowing Venturi 114 (Venturiacts as a flowmeter as well as a good flow mixer); the well-mixedoil-water liquid is enriched at the top blind flange location by theblind flange 112 where the first EM sensor 102 is installed. Liquidtends to collect near the blind flange 112 as the flow changes directionto exit through an outlet conduit 110. However, this location may not bedesirable in some cases where the vertical blind flange (and the EMsensor and its electronics enclosure) needs to be removed to provideaccess for the flowmeter system (such as one based on Venturi andgamma-ray). A second EM sensor 116 is shown installed on the side wall118 (in substantial azimuthal alignment with the bottom horizontalblind-tee 108) downstream of the divergent section 120 of the verticalVenturi 114. A third EM sensor 122 can be installed in the divergentsection 120, on side wall 118 at the tapered portion thereof. Thus, oneor more EM sensors can be installed in a wall of a Venturi device at adivergent section thereof. A fourth EM sensor 124 can be installed atthe throat section 126 of the Venturi 114, near the divergent section120 where flow velocity/oil-water mixing is at the highest, if thethroat section 126 of the Venturi 114 is sufficiently long to allowinstallation of the EM sensor 124. Computational fluid dynamicsmodelling and experimentation have revealed that a thicker liquid walllayer can be found at the inlet section and the convergent section,upstream of the throat section, of a Venturi device, for example at theVenturi inlet after the right-angle turn of a bottom blind 108 in aninlet line 104, in substantial azimuthal alignment with the bottom blind108, which may be a blind pipe or flange. A fifth EM sensor 128 can beinstalled at the side wall 118 at the convergent section 106 of theVenturi 114, in the tapered portion thereof and substantiallyazimuthally aligned with the blind 108. A sixth EM sensor 130 can beinstalled at the Venturi inlet section 132, upstream of the convergentsection 106 and substantially azimuthally aligned with the blind 108.The sixth EM sensor 130 located at the Venturi inlet will measure athicker liquid layer than that located at the Venturi convergent section106, which is advantageous for the EM sensor to achieve good watersalinity and WLR measurements over a wider gas-volume-fraction (GVF)range. The fifth and sixth EM sensors 128 and 130 can be installednon-invasively at the convergent and inlet sections of the Venturi 114so that fluid flow into the Venturi 114, and any resulting differentialpressure measurements thereof, would not be disrupted by the sensors.The fifth and sixth EM sensors 128 and 130 can be installed at the blindpipe 108 so that fluid flow into the Venturi 114, and any resultingdifferential pressure measurements thereof, would not be disrupted bythe sensors. Any combination of one or more of the EM sensors 102, 116,122, 124, 128, and 130 can be used, depending on the needs of individualprocesses.

The side wall EM sensor locations at Venturi throat 126, at thedivergent section 120, or downstream of the divergent section 120 mayhave a decreased amount of liquid near pipe walls at high GVF (wet-gas)conditions, leading to a reduced capability to detect early water, brinesalinity and to measure the WLR accurately. A liquid-enrichment meanslocal to the front aperture of the EM sensor may be desirable in someembodiments. It should also be noted that, in some cases, an EM sensormay be used with a vertical straight pipe section (without a Venturidevice) downstream of a horizontal blind pipe; the second to sixth EMsensor positions may have little difference in terms of the amount ofnear-wall liquid. A liquid-enrichment means local to the front apertureof the EM sensor may or may not be used in such cases.

The body of the front piece may be made of H₂S-resistant alloy such asInconel. The center conductor (coaxial or concentric conductor) may bemade of Inconel or Cemented Carbide (also H₂S resistant). The glass- orceramic-seal insulator material may be appropriately chosen (such asborosilicate glass, solar glass, alumina ceramic or the like) towithstand the desired process pressure and temperature, be resistant tosalts and various chemicals in produced fluids, and to have stabledielectric constant and low electrical loss. The inner diameter of theprobe body and the outer diameter of the center conductor are sizedappropriately, together with the dielectric constant of the sealmaterial (including a coaxial conductor-insulator insert in the probebody for use with a short glass-metal seal, FIG. 3A), to form a coaxialtransmission-line structure of a desired characteristic impedance, suchas 50 Ohm. The coefficients of thermal expansion of the probe body, theconcentric conductor and the insulator are appropriately chosen toachieve insulator-to-metal pressure seal.

FIG. 2 is an elevation view of a front piece 200, according to oneembodiment. The front piece 200, made of Inconel, has a probe portion202 and a connection portion 204 for connecting to RF sources. Anappropriately chosen off-the-shelf RF connector 210, here a coaxialconnector, may be attached to the connection portion 204.

The connection portion 204 of the front piece 200 has a seal face 216that faces the probe portion 202 in the axial direction of the frontpiece 200. The seal face 216 has a groove 218 (not visible in FIG. 2 )that extends around a proximal end 220 of the probe portion 202 toaccommodate a seal member (not shown) in the groove 218. The seal face216, and seal member disposed therein, are for sealing around a portinto which the probe portion 202 extends to expose the probe (not shown)within the probe portion to the flowing fluid.

FIG. 3A is a cross-sectional view of a front piece 300 for an EM probeassembly according to another embodiment. The front piece 300 is similarto the front piece 200 of FIG. 2 in many ways. The front piece 300 hasthe probe portion 202 and the connection portion 204, which togetherdefine a probe housing 302. The connector 210 is attached to the probehousing 302 at the connection surface 214. Here, a recess 316 formed inthe connection surface 214 accommodates the connector 210, but theconnector 210 can be attached to a flat (i.e. un-recessed) connectionsurface 214, as in FIG. 2 . The connector 210, which may be a standardoff-the-shelf RF connector, is fastened to the connection portion 204,in this case using bolts or screws.

The probe housing 302 has an axial bore 308 that houses an insulationassembly 310 and a probe 312, which may be a center or a concentricconductor, and made from for example an appropriate-material metal pinwith a suitable outer diameter. The axial bore 308 is disposed throughthe probe housing 302 from a first end 314 of the probe housing to asecond end 317 of the probe housing, opposite from the first end. Theaxial bore 308 is formed through the probe housing 302 such that acentral axis of the probe housing 302 is coincident with an axis of theaxial bore 308. The insulation assembly 310, in this case, has a firstinsulator 318 and a second insulator 320, both of which are disposed inthe axial bore 308 surrounding the probe 312. The probe 312 is anelectrical conductor that is disposed within the insulation assembly310, in a passage formed through the first and second insulators 318 and320 of the insulation assembly 310, along an axis thereof, which issubstantially coincident with the axis of the insulation assembly 310and the probe housing 302, from the first end 314 of the probe housing302 to the second end 317, and beyond into the connector 210 to allowelectric power, for example RF power, to be connected to the probe 312.At least one of the first and second insulators 318 and 320 has an outerradius substantially the same as an inner radius of the axial bore 308so that the insulation assembly 310 can seal the axial bore 308 againstprocess fluids, to which the probe 312 is exposed when the front piece300 is installed in an operating facility, for example in a conduit orflow structure. In this case, the first insulator 318 is a shortglass-metal seal and the second insulator 320 is a coaxialconductor-insulator. Ceramic-metal material can be used in place ofglass-metal for the first insulator 318. The first insulator 318 is hereconfigured to contact the probe 312 and the inner wall of the axial bore308 to seal the axial bore 308, and the second insulator 320 may beconfigured with a small cylindrical gap around the probe 312 between theprobe 312 and the second insulator 320, as shown here, to maintain acharacteristic electrical impedance of the probe 312. The length of thefirst insulator 318 and the second insulator 320 may be selectedaccording to appropriate design criteria. The probe housing 302 has theseal face 216, with the groove 218 for accommodating a seal member.Here, the probe housing 302 is shown without a liquid enhancementfeature such as the wall member 402 shown in FIG. 4A. A liquidenhancement feature may be added to the probe housing 302, if desired.

FIG. 3B is a cross-sectional view of a front piece 350 according toanother embodiment. The front piece 350 is similar to the front piece300 and the front piece 200 in most respects. The front piece 350 has asingle insulator 352, instead of the insulation assembly 310 of FIG. 3A.The insulator 352 is a glass-metal (or ceramic-metal) insulator disposedin the axial bore 308. The insulator 352, in this case, extends from thefirst end 314 of the probe housing 302 to the second end 317, andcontacts the connector 210. The insulator 352 has a concave surface 354at the first end 314 of the probe housing 302 to minimize stress-inducedcracking of the insulator 352. The concave surface 354 is recessedwithin the first end 314, and the probe 312, in this case, is open toprocess fluids at a slightly recessed position relative to the first end314 of the probe housing 302. The depth of the recess is typically 0.1to 0.5 mm.

FIG. 4A is a perspective cross-sectional view of a front piece 400according to another embodiment. The front piece 400 is similar to thefront piece 350 of FIG. 3B, and to the front pieces 300 and 200, in mostrespects. In this case, the front piece 400 has a wall member 402 thatis removable. The wall member 402 provides liquid enhancement bycreating a turn in flow of the multiphase fluid to encourage fluids tocoagulate according to density differences. The front piece 400 has aprobe portion 404 with a first section 406 and a second section 408. Thefirst section 406 has a first outer radius and the second section 408has a second outer radius larger than the first outer radius. The firstsection 406 extends in an axial direction of the front piece 400 from afirst end 412 of the probe portion 404 to the second section 408. Thesecond section 408 extends from a second end 414 of the probe portion404, at the connection portion 204, to the first section 406. The firstsection 406 and the second section 408 meet at a wall 410 that extendsradially outward from the first section 406 to the second section 408.In this case, the wall 410 extends only in a radial direction, but insome cases, the wall 410 may also extend some distance in the axialdirection to form a frustoconical wall.

The removable, replaceable, wall member 402 is disposed around the firstsection 406 and has a wall portion 416 that extends beyond the first end412. The wall portion 416 extends from a ring portion 418 of the wallmember 402. The wall portion 416 extends partway around thecircumference of the ring portion 418 to form, in this case, acylindrical wall. When installed in a flow system such as that of FIG. 1, the wall member 402 is generally oriented such that the wall portion416 is located at a downstream, relative to a flow path of the flowingmultiphase fluid, of the probe portion 404. The wall portion 416 forcesthe flowing multiphase fluid to turn to encourage liquid to collect nearthe first end 412 of the probe portion 404. Enhancing the presence ofliquid at the first end enhances detection and analysis of liquidproperties in the flow multiphase fluid.

Here, as an illustration, the wall portion 416 has an inner radius thatis less than the first outer radius of the first section 406 of theprobe portion 404, such that the wall portion 416 partially overlaps anend surface 420 of the probe portion 404, at a peripheral regionthereof. The ring portion 418 has an axial length substantially equal toan axial length of the first section 406 of the probe portion 404, suchthat the ring portion 418 substantially covers the outer cylindricalsurface of the first section 406. The ring portion 418 has an outerradius that is substantially the same as an outer radius of the wallportion 416, such that an outer surface of the ring portion 418 and anouter surface of the wall portion form a continuous outer surface. Theouter surface of the wall portion 416 and the ring portion 418 have aradius that is, in this case, substantially the same as the second outerradius of the second section 408 of the probe portion 404. In this case,therefore, the outer surface of the second section 408 and the outersurface of the ring portion 418 and the wall portion 416 form a surfacewith substantially constant outer radius. Because the wall portion 416overlaps a portion of the end surface 420 of the probe portion 404, thering portion 418 has an inner radius larger than the inner radius of thewall portion 416.

The wall member 402 is removable by sliding the wall member 402 off theend of the first section 406 of the probe portion 404. By making thewall member 402 removable and replaceable, other wall members havingdifferent configurations can be used for liquid enhancement tocorrespond with different desired process features. FIG. 4B is aperspective cross-sectional view of a front piece 430, according toanother embodiment. The front piece 430 has a removable wall member 432,according to another embodiment. The wall member 432 is similar to thewall member 402 of FIG. 4A. The front piece 430 and the front piece 400have the same probe housing, illustrating how a plurality of removable,replaceable wall members can be used for liquid enhancement with oneprobe housing. The wall member 432 has a wall portion 436 with a smallerangular extent than the wall portion 416 of the wall member 402 of FIG.4A.

The wall portion 416 is shown here as a cylindrical extension protrudingoutward from the first end 412 of the probe portion 404. Alternativeconfigurations can be used for liquid enhancement. The wall portion 416can be flat, rather than curved, or curved in a non-cylindrical manner.The wall portion 416 can have a flat wall with end tabs that extend atangles from the wall, for example at right angles. The wall portion 416is shown here extending directly outward from the first end 412 in adirection parallel to the axial direction of the front piece 400. Inother embodiments, the wall portion 416 can extend in a direction thatis not parallel to the axial direction, but instead makes an angle withthe axial direction. For example, depending on the needs of anindividual process, the wall portion 416 might angle toward or away fromthe probe 312. The wall portion 416 is shown here as a continuous wall,but alternative configurations can use a discontinuous wall. Gaps orholes can be provided in the wall portion 416 at convenient locations insome embodiments, while other embodiments might use rod-like extensions,parallel to, perpendicular to, or forming another angle with, the axialdirection of the front piece 400 to form a partial or discontinuouswall. The wall portion 416 is also shown here as having a rectangularprofile when viewed toward the broad side of the wall portion 416.Alternative configurations might use a wall with a curved profile whenviewed from that direction. Liquid enhancement can be obtained using anytype of protrusion that provides a local turning or recirculation of thefluid flow to encourage collection of liquid near the probe 312. Thewall member 402 may be oriented such that the wall portion 416 islocated at an upstream location, relative to a flow path of the flowingmultiphase fluid, of the probe portion 404.

Orientation of the wall member 402 can be aided by an orientationfeature (not shown) that can be provided in the ring portion 418 of thewall member 402, with a corresponding, matching, orientation feature(not shown) provided in the outer wall of the first section 406 of theprobe portion 404 to engage with the orientation feature of the wallmember 402. The orientation features can be matching bumps, ridges,recesses, grooves, and the like. Alternately, orientation of the wallmember 402 may be secured by use of a fastener, such as a grub screw(not shown).

FIG. 4C is a perspective cross-sectional view of a front piece 460,according to another embodiment. The front piece 460 has the same probehousing as the front piece 430 and the front piece 400, with the probeportion 404 that can receive a removable member. In this case, a ringmember 462 is disposed around the first section 406 of the probe portion404. The ring member 462 is not a liquid enhancement feature, having nowall portion to protrude into the fluid flow. The ring member 462 can beused at times when no liquid enhancement is desired to fill the gapbetween the first section 406 of the probe portion 404 and the innerwall of the port into which the front piece 460 is inserted. The ringmember 462 prevents unwanted materials, such as sand and other solids,from collecting in the gap by filling the gap.

The wall members 402 and 432, and the ring member 462, can be made ofany convenient material. In some cases, a low cost erosion-resistantthermoplastic, such as polyether ether ketone (PEEK), can be used.Metals, erosion-resistant ceramics, and composites, can also be used.The members can be molded, cast, sculpted, or 3-D printed usingappropriate materials. An alignment feature (not shown), such as agroove, ridge, bump, notch, pin, grub screw, or other appropriatefeature, can be formed in, or provided for, any of the members 402, 432,and 462, as needed. It should be noted that a ring member, such as thering member 462, may have other functional features that benefit fromorientation, even though the ring member 462 does not have a liquidenrichment wall portion. It should also be noted that, instead of usinga removable, replaceable wall member, the first portion of the frontpieces 200, 300, 350, 400, 430, and/or 460 could have an integral wallportion that extends along the axial direction of the front piece awayfrom the respective first ends of the probe portions thereof. In suchembodiments, the front piece itself can have orientation features tohelp orient the wall portion according to fluid flow direction. Theorientation features can be provided in the probe portion or theconnection portion of the front piece.

Reduction in the complexity and cost of the EM coaxial probe sensor foruse with a desired design pressure such as 5000 psi may also be desired.This may be accomplished by removing an integral coaxial feedthroughwith a second glass-metal or ceramic-metal seal (as disclosed in U.S.Pat. No. 9,638,556). A polished concaved front (glass) surface at aprobe body (front piece) may be needed for a long e.g. glass-metal sealdesign (FIG. 3B) to avoid stress-induced fine cracks forming in glass(as disclosed in U.S. Pat. No. 10,330,622). Reducing the amount ofexpensive (Inconel) alloy used for the probe body (front piece) andavoiding having a circumferential groove (as disclosed in U.S. Pat. No.10,330,622) may also be desirable.

FIG. 5 is a perspective cross-sectional view of a probe assembly 500according to one embodiment. The probe assembly 500 has a first member502 with a probe portion 504 and a connection portion 506, similar tothe front pieces described above. The probe portion 504 has a centralbore 508 with a probe 510, shown as a concentric and/or coaxialconductor here, and a pressure-resistant insulator 512 surrounding theprobe 510, similar to the front piece 350. Here, the pressure-resistantinsulator 512 is of the long length variety described in connection withFIG. 3B. The probe 510 extends from an opening 514 at a distal end 516of the probe portion 504 into the connection portion 506. The probe 510,which may be a coaxial conductor, is exposed at the opening 514 tocontact process fluids for analysis thereof. The connection portion 506has a connector 518 coupled to a distal end 520 of the connectionportion 506 and a seal face 522 with a groove 524 extending around theprobe portion 504. The seal face 522 here is the same as the seal face216 of FIG. 2 , but can be configured in any convenient way. Theconnector 518 is substantially the same as the connector 210, but anyconvenient connector can be used here. The groove 524 accommodates aresilient seal member, such as an O-ring or C-ring, that can be insertedinto the groove 524. When pressed against a pipe wall around an openingfor the probe portion 504, the seal member seals the opening. Here, thefirst member 502 has no liquid enhancement feature, such as theremovable wall member 402

The probe assembly 500 has a second member 530 shown engaged with thefirst member 502. The second member 530 is a conduit member that has anexternal thread 532 and an internal passage 534 from a first end 536 ofthe second member 530 to a second end 538 of the second member 530opposite from the first end 536, the internal passage 534 having asmooth wall 540 at the first end 536 and an internal thread 537 at thesecond end 538. The internal thread 537 can be used to couple to a cablegland 550 for securing an RF cable 552. The second member 530 has afirst portion 542 with a first outer radius, the first portion 542bearing the external thread 532, and a second portion 544 with a secondouter radius that is less than the first outer radius in thisillustration. Here, the second portion 544 is unthreaded along the outerwall, but any features, such as a hexagonal cross-section, can beincorporated into the outer wall of the second portion 544 as needed,for example to facilitate applying torque to the second member 530 toengage the threads 532 with a threaded port (not shown) to applycompression and retain the first member 502.

The second member 530 is shown engaged with the first member 502 in anoperating configuration. When installed, the second member 530 directlycontacts the first member 502, and the external thread 532 of the secondmember engages with a threaded bore. The seal face 522 of the firstmember 502 contacts a pipe wall, flange, or other flow containmentstructure, and progressive engagement of the external thread 532 of thesecond member 530 presses the first member 502 against the flowcontainment structure to form the seal around the probe portion 504.

The first member 502 can be a front piece, as described in connectionwith FIGS. 2-4C, and the second member 530 can be a back piece. Thesecond member 530 holds the first member 502 in place with the probeportion 504 protruding through an opening in a flow containmentstructure, such as a pipe wall or flange. Engagement of the externalthread 532 of the second member 530 provides a sealing force between theseal face 522 and the flow containment structure to press the sealmember (not shown) in the groove 524 against the flow containmentstructure, thus providing compressive support to the first member 502.The internal passage 534 provides a conduit for the RF cable 552, here acoaxial cable, to make electrical connection to the connector 518. Theprobe 510, here a center conductor, extends through the first member 502into the connector 518 to make RF connection.

FIG. 6 is a perspective cross-sectional view of a probe assembly 600according to another embodiment. In this case, the probe assembly 600uses a flange member 602 for attachment to a flow containment structure.The probe assembly 600 uses a first member 604 similar to the frontpiece 350 of FIG. 3B with a conduit member 605 that serves as a holdinggland and conduit for the RF cable 552 that connects to the connector518. Here, the flange member 602 is the second member that appliescompression to the first member 604 against the conduit wall to seal theport. The flange member 602 has an internal bore 606 formed through theflange member 602 in an axial direction thereof to provide access to theconnector 518 for connection of the RF cable 552. The conduit member 605has an external thread 608 that engages with an internal thread 610formed in the bore 606. The RF cable 552 may engage directly with theconnector 518, or as shown here an adaptor 554 may be used to connectthe RF cable 552 with the connector 518. When installed, the flangemember 602 makes direct contact with the first member 604, at a distalend 614 of the connection portion 204, and is bolted to the flowcontainment structure at bolt holes 612 to provide sealing force betweenthe seal face 522 and the flow containment structure. The cable gland550 can also be used here.

It should be noted that in some embodiments, the flange member 602 andconduit member 605 may be one second member, a unitary object. In suchcases the second member would have a flange portion and a conduitportion that extends axially from a center of the flange portion. Ingeneral, the probe assemblies described herein have a first member witha probe portion that is disposed through an opening in a conduit (orflange, or blind pipe) for exposure to a flowing fluid. The conduit hasa first coupling structure, so that a second member of the probeassembly can couple with the first coupling structure to apply pressureto the first member of the probe assembly. The second member maygenerally comprise a flange. Additionally, or instead, the second membermay comprise a conduit. The second member can be a conduit member, aflange member, a combination of a conduit member and a flange member, ora unitary object that has a flange portion and a conduit portion. Thesecond member generally has a second coupling structure for couplingwith the first coupling structure to enable application of compressionto the first member. Engagement of the coupling structures isillustrated below.

FIG. 7 is a perspective cross-sectional view of an apparatus 700 foranalyzing a flowing multi-phase fluid. The apparatus 700 has a probeassembly 702 with the first member 604 and the second member 530installed in a flange 704 as the flow containment structure. The probeassembly 702 is here installed off-center in the flange 704 toillustrate the flexibility of locating the probe assembly 702 at anyconvenient liquid-rich location of the flow containment structure. Theapparatus 700 can be installed as the first EM sensor 102 of FIG. 1 .

Here, the first coupling structure is a threaded port 706, through whichthe probe portion of the first member 604 is disposed. The second member530, here a conduit member, has a second coupling structure that is anexternal thread for coupling with the first coupling structure to applycompression to the first member 604 against the wall of the conduit, inthis case a shelf of the bore into which the probe portion is extended.

FIG. 8 is a perspective cross-sectional view of an apparatus 800 foranalyzing a flowing multiphase fluid. In this case, the probe assembly702 is installed through the side of a tubular flow containmentstructure 802, which may be a flange or pipe wall. The first member 502is disposed in a port 804 formed in the flow containment structure 802that has three sections. A first section 805 admits the probe portion504 into contact with the flowing multiphase fluid. A second section 806houses the connection portion 204 and the first portion 542 of thesecond member 530. The second section 806 has an internal thread as thefirst coupling structure to engage with the external thread 532 of thefirst portion 542 as the second coupling structure. The second section806 meets the first section 805 at a shelf 808 that contacts the sealface 216 of the connection portion 204. As noted above, the secondmember 530 presses the seal face 216 of the first member 502 against theshelf 808. The second section 806 may have an inner radius that islarger than an inner radius of the first section 805. A third section810 of the port 804 may have an inner radius that is larger than theinner radius of the second section 806, forming an annular gap 812between the third section 810 of the port 804 and the second portion 544of the second member 530 to provide access to install and remove thesecond member 530.

FIG. 9 is a perspective view of an apparatus 900 for analyzing a flowingmulti-phase fluid according to another embodiment. Here, the probeassembly 600 is installed in a pipe wall upstream of the convergentsection 904, at an inlet section 910, of a Venturi device 902, as a flowcontainment structure. The probe assembly 600 is installednon-invasively to the fluid flow. The probe assembly 600 issubstantially azimuthally aligned with a horizontal blind-tee 909 of theinlet pipe 104 to the Venturi device 902. At the inlet section 910, onthe side of the blind-tee 909, a layer of liquid of the multiphase fluidis thicker than that along the wall opposite from the probe assembly600. As fluid flows from the inlet 104 into the vertical flow pipe 914,the change in flow direction encourages fluids of different densities tosegregate in an interior 916 of the pipe 914, with higher density liquidtending to collect along the wall of pipe 914 closest to blind-tee 909.A port 906 formed in the flow containment structure has a fasteningsection 908 that accommodates the flange member 602 as a back flange forbolting directly to the pipe wall. In this case, the first couplingstructure is a plurality of bores 918 formed in the wall of the inletsection 910, and the second coupling structure is a plurality of holes920 in the flange member 602, and a plurality of fasteners 922, in thiscase bolts, disposed through the holes 920 into the bores 918. Here, theprobe assembly 600 is shown with no local liquid enhancement to minimizeflow disruption at the inlet of the Venturi device 902. In thisembodiment, the horizontal end blind-tee 909 and the vertical flow pipe914 extending from the blind-tee 909 and inlet pipe 104 to the Venturidevice 902 act as liquid (or liquid fraction) enhancement structure,because the liquid layer that accumulates along the side of the verticalpipe 914 in which the probe assembly 600 is installed is thicker thanalong the wall opposite from the probe assembly 600, and such contrastin liquid richness continues into at least the inlet section of theVenturi device 902.

FIG. 10 is a graphical depiction 1000 of a multiphase fluid 1002 flowingin a measurement apparatus or a Venturi device 1014 coupled to ablind-tee section 1010 having a blind flange 1008, the graphicaldepiction showing 1000 liquid content of the multiphase fluid atdifferent locations along the vertical Venturi 1014. This graphicaldepiction is in color to allow viewing of the different liquid contents.Fluid flow is in the direction of arrow 1006. Here, as the gas-fractionlegend indicates, thicker liquid layers form along the side 1011 of thevertical Venturi 1014 that is aligned with the blind flange 1008 of theblind-tee 1010 installed upstream of an inlet of the Venturi device1014. Thinner liquid layers appear along the opposite side 1012 of theVenturi device 1014. The model that gave rise to the graphical depiction1000 indicates that installation of EM probes at the locations of thefifth and sixth EM probes 128 and 130 of FIG. 1 can successfully engagewith a liquid-rich layer for reliable analysis of the multiphase fluid.

The EM probes, probe assemblies, and flow systems shown herein generallyuse a method of analyzing a flowing multiphase fluid for determiningwater properties such as water conductivity or salinity and WLR, themethod including disposing an open-ended microwave probe assembly of thesort described herein in a port, which may be threaded, formed in a flowcontainment structure carrying the flowing multiphase fluid, andenergizing the probe assembly using radio frequency (RF) energy. Theprobe assembly is generally located at or near a liquid-rich region ofthe flow containment structure. A liquid fraction enhancement structuremay be used; the liquid enhancement structure is a structure of the flowsystem that encourages liquid to collect near a wall region of the flowcontainment structure. As noted above, enhancement of the amount orfraction of liquid in the flow improves analysis of the liquid. Theliquid fraction enhancement structure, such as a horizontal endblind-tee to vertical pipe transition, typically changes a flowdirection of the multiphase fluid, allowing density differences of theliquid and gas phases to aggregate the liquids and gases, at least to anextent. In some cases, a local liquid enhancement structure can beprovided as part of the probe assembly to enhance collection of liquidat the open end of the probe assembly. A single probe assembly can beinstalled in a flow system, or multiple probe assemblies can be used tocompare results. Comparing results can be helpful in improving qualityand repeatability of data from the probes, and different probeassemblies can be used to focus on different aspects of the multiphasefluid flow.

The EM probes described herein are frequently shown in azimuthalalignment with a blind section of a blind-tee to capture liquid fractionenhancement resulting from a turning of the fluid flow. It should benoted that the azimuthal alignment does not have to be absolutealignment. The alignment can be substantial, so that a few angulardegrees of misalignment is tolerated. Liquid fraction enhancement isgenerally found along the inner wall on the side of the conduit nearestthe blind section since that side of the conduit is along the outerradius of the turn in the flow path of the fluid. An EM probe can beinstalled out of absolute alignment with the blind section, and can findliquid enhancement along the inner wall on the “blind side” of theconduit.

Although the preceding description has been described herein withreference to particular means, materials and embodiments, it is notintended to be limited to the particulars disclosed herein; rather, itextends to all functionally equivalent structures, methods, and uses,such as are within the scope of the appended claims.

What is claimed is:
 1. A probe assembly to measure liquid properties ina multiphase fluid flowing in a conduit, the probe assembly comprising:a first member with a probe portion and a connection portion, the probeportion having a central bore with a conductor and a pressure-resistantinsulator surrounding the conductor, the conductor extending from anopening at a distal end of the probe portion into the connectionportion, the connection portion having a connector coupled to a distalend of the connection portion, the connection portion having a seal facewith a groove extending around the probe portion; and a second memberthat, when assembled, is in direct contact with the first member at thedistal end of the connection portion to apply compression to the firstmember to retain the first member against a wall of the conduit.
 2. Theprobe assembly of claim 1, wherein the second member has a threadedwall.
 3. The probe assembly of claim 2, wherein the second member has afirst portion, the threaded wall being an external wall of the firstportion, and a second portion having a feature incorporated into anouter wall of the second portion to facilitate applying torque to thesecond member.
 4. The probe assembly of claim 1, further comprising aremovable wall member that surrounds the distal end of the probe portionand has a wall portion that extends from a portion of the removable wallmember.
 5. The probe assembly of claim 1, wherein the first membercomprises a corrosion-resistant metal material, the conductor comprisesa corrosion-resistant material, and the pressure-resistant insulator isa glass or ceramic material.
 6. The probe assembly of claim 1, whereinthe first member, the conductor, and the insulator are made of materialschosen to have coefficients of thermal expansion that promoteinsulator-to-metal pressure seal.
 7. The probe assembly of claim 1,wherein the second member is selected from a flange member, acombination of a flange member and a conduit member, or a unitary memberhaving a flange portion and a conduit portion.
 8. An apparatus toanalyze a flowing multiphase fluid, the apparatus comprising: anopen-ended microwave probe assembly disposed in fluid communication witha conduit through a wall of the conduit, the conduit having a firstcoupling structure, the probe assembly comprising: a first member with aprobe portion and a connection portion, the probe portion having acentral bore with a conductor and a pressure-resistant insulatorsurrounding the conductor, the connection portion having a coaxialconnector coupled to a distal end of the connection portion andconnected to the conductor, the connection portion having a seal facewith a groove extending around the probe portion, and a seal memberdisposed in the groove, the probe portion extending through the firstcoupling structure and the seal face of the connection portion insealing contact with the wall of the conduit; and a second member havinga second coupling structure to engage with the first coupling structureat the distal end of the connection portion to apply compression to thefirst member to retain the first member against the wall of the conduit.9. The apparatus of claim 8, wherein the first coupling structure is athreaded port, the second member is a conduit member, and the secondcoupling structure is an external thread on an outer wall of the secondmember.
 10. The apparatus of claim 9, wherein the first couplingstructure is a plurality of bores formed in the wall of the conduit, thesecond member comprises a back flange, and the second coupling structureis a plurality of holes in the back flange and a plurality of fastenersdisposed through the holes and into the bores.
 11. The apparatus ofclaim 8, wherein the conduit comprises a blind-tee, and the open-endedmicrowave probe assembly is disposed at a location of the conduit thatis azimuthally aligned with a blind portion of the blind-tee.
 12. Theapparatus of claim 8, further comprising a wall member that surroundsthe distal end of the probe portion and has a wall portion that extendsfrom a portion of the wall member.
 13. The apparatus of claim 8, whereinthe conduit includes a liquid fraction enhancement structure and theprobe portion is disposed at the liquid fraction enhancement structure,wherein the liquid fraction enhancement structure is a pipe end cap or ablind flange.
 14. The apparatus of claim 8, wherein the conduit includesa liquid fraction enhancement structure and the probe portion isdisposed at the liquid fraction enhancement structure, wherein theliquid fraction enhancement structure is a horizontal blind-tee coupledto a vertical pipe section.
 15. The apparatus of claim 14, wherein theopen-ended microwave probe assembly is located in a first portion of thevertical pipe section or is located in a second portion of an inlet or aconvergent section of a vertical Venturi device.
 16. The apparatus ofclaim 8, wherein the open-ended microwave probe assembly is located infirst portion of a Venturi device on a throat or divergent sectionthereof, and the probe portion has a wall member that surrounds thedistal end of the probe portion and has a wall portion that extends froma portion of the wall member.
 17. The apparatus of claim 8, wherein theconduit comprises a multiphase flowmeter based on microwavetransmission-resonance measurement, electrical impedance measurement,X-ray or gamma-ray measurement, or a combination thereof.
 18. A device,comprising: a probe portion, wherein the probe portion comprises acentral bore with a conductor and a pressure-resistant insulatorsurrounding the conductor; and a connection portion coupled to the probeportion, wherein the conductor extends from an opening at a first distalend of the probe portion into the connection portion, wherein theconnection portion comprises a connector coupled to a second distal endof the connection portion, wherein the connection portion comprises aseal face with a groove extending around the probe portion; and aremovable wall member coupled to a proximate end of the probe portionand protruding from the proximate end of the probe portion to collectliquid near the proximate end of the probe portion.
 19. The device ofclaim 18, wherein the removable wall member is disposed at an angle toan axial direction with respect to the probe portion.
 20. The device ofclaim 18, wherein the proximate end of the probe portion comprises aconcave surface.